Forensic Issues: Bruising

On every crime show where a murder has occurred, there's usually a big scene with the medical examiner asserting time of death or determining the time of an injury. In pediatrics, this becomes important when we look at timing a child abuse injury so we can place who was with the child during the suspected event.

The question is, can bruising give an exact time for the injury?




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 Bruising happens when an object comes into contact with the skin, and the small capillaries underneath break open and cause bleeding. Generally, patterned shaped bruises are more suspicious for intentional injury. For something to make a pattern on the skin, it generally needs speed or velocity to imprint the pattern onto the skin. For instance, it is far different if I tap you with a belt versus swinging and slapping it down.

Point blank, bruising is not a good way to determine time of injury. Bruising is influenced a lot by the individual person. Are they on blood thinners? Do they normally heal quickly? Age factors influence speed of healing as well. Bruising can give a time frame but color of bruising is also open to interpretation. Here's one set of guidelines.

Color of Bruise
Red-- swollen/tender: 0-2 days
Blue/Purple: 2-5 days
Green: 5-7 days
Yellow 7-10 days
Brown 10-14 days

As you can see, 48 hours is a large time frame. In the case of pediatrics, imagine the potential of how many people could have come into contact with an infant.

Interesting bruising fact: Bruises generally heal from the inside out. If you watch a bruise you have, you'll notice they become lighter at the center as healing progresses.

Did you think bruises could give an accurate time frame for injury?